The NHS may have too few staff and too little money to deliver Government pledges for a “truly seven-day NHS” by 2020, leaked Department of Health documents reveal.

Confidential papers drawn up for Jeremy Hunt and other ministers in late July detail a list of risks to the Government's manifesto pledge.

Civil servants who drew up the "risk register" and other documents assessing the policy, said the greatest danger was lack of NHS staff, “meaning the full service cannot be delivered”.

The documents, obtained by the Guardian and Channel 4 News, also suggest staff could provide an obstacle to such changes, because "they do not believe in the case for change”.

Ministers have promised to change the way NHS services are run, and to boost staff numbers at weekends, after warning of a "weekend effect" with unacceptable variations in care, depending on when people fall ill.

The policy has seen the Government at loggerheads with the British Medical Association, which is now drawing up plans for rolling strikes during the autumn.

We are confident our programme for a safer seven-day NHS is on track‎, and will deliver real benefits for patientsDepartment of Health source

The leaked documents also discuss risks that the policy fails to improve care at weekends, and that patients notice no difference.

A DoH source said: "A risk register by definition details all potential issues under a worst-case scenario to help the government develop robust plans to ensure we meet our promises to the electorate, but we are confident our programme for a safer seven-day NHS is on track‎, and will deliver real benefits for patients.”

In evidence to a Commons Health Select Committee on winter pressures, they claim that a “national imbalance” between patient demand for services, and the funding received, means even the best hospitals will soon become unable to cope.

The evidence comes amid growing concern about pressures on hospitals, which are already in the grip of the worst levels of bed-blocking on record.

Yesterday plans emerged for hospitals to cancel thousands of operations and appointments in a desperate bid to stop the NHS "buckling" this winter.

Health officials are drawing up contingency measures to attempt to safeguard emergency care by diverting senior doctors from operating theatres into wards and A&E departments as winter sets in.

The planning emerged in evidence to the select committee, which will next month open hearings examining the ability of the NHS to cope this winter.

The seven-day policy has seen the Government at loggerheads with the British Medical Association, which is now drawing up plans for rolling strikes during the autumnCredit:
Oli Scarff/Getty Images

But in separate evidence to the committee, NHS Providers – which represents almost all NHS hospitals - said radical reform of the funding system was needed to prevent services failing.

Under NHS funding systems, money is allocated to hospitals via more than 200 clinical commissioning groups.

But under a national tariff which sets the rates for treatment, hospitals recoup less for their emergency admissions if they have more than was planned.

The system was set up in a bid to encourage healthcare planners focus resources into help treating patients in the community, and reducing unnecessary admissions.

However, NHS Providers says the tariff is not realistic, and ignores the fact that once patients are in hospital, their treatment needs to be paid for.

In their submission they say: “Our central message is that there is a fundamental mismatch between the demand for emergency services and the resources made available for these services.

“We do acknowledge there are opportunities for all providers to improve the services they deliver to patients. However, unless this national imbalance between demand for services and resources is redressed, even the most efficient and forward-looking organisations will be unable to cope with the increasing pressure on emergency care.”

It is hard to see how we can maintain high levels of A&E performance for patients within the funding we have availableSivakumar Anandaciva

The organisation is calling for increased funding for key frontline services, such as A&E, and an end to a system which pays hospitals reduced rates for seeing more patients than was planned, and to penalty fines for those who readmit too many patients.

Sivakumar Anandaciva, NHS Providers head of analysis said: “A&E departments up and down the country are being placed under increasing pressure each year. Demands for their services are increasing but hundreds of millions of pounds in funding continues to be withheld from them.”

Highlighting performance problems across the NHS, he said even the best hospitals were struggling.

Latest figures show the number of elderly people needlessly stuck in hospital has reached record levels, with an 80 per cent rise in bed days lost to delayed discharges in five years. The monthly figures also show just 90.5 per cent of A&E patients were seen within four hours, against a target of 95 per cent - the worst June figures on record.

Mr Andandaciva said: “Ultimately, you get what you pay for and it is hard to see how we can maintain high levels of A&E performance for patients within the funding we have available.”

A spokesman for NHS England said: "Fewer hospitals reported serious operational issues this winter than last and there was a significant reduction in trolley waits. Lobbying about the emergency tariff set by NHS Improvement completely misses the point that this year an extra £1.8 billion of funding is being allocated to hospitals providing emergency care, over and above their tariff payments.

"Sucking more money out of GP services into hospitals as has happened over the last decade will only perpetuate these rising pressures and is at best a sticking plaster solution to a more fundamental set of challenges that requires stronger primary care and social care working in a joined up way with A&E departments."